Re: hardare config question
| От | Erik Myllymaki |
|---|---|
| Тема | Re: hardare config question |
| Дата | |
| Msg-id | 44566426.2040707@aviawest.com обсуждение исходный текст |
| Ответ на | Re: hardare config question (Scott Marlowe <smarlowe@g2switchworks.com>) |
| Список | pgsql-performance |
guess who just bought a 3ware BBU on ebay... Thanks for all the posts, consider me educated! (on the importance of BBU on RAID controllers, anyway) :) Scott Marlowe wrote: > On Mon, 2006-05-01 at 13:22, Tom Arthurs wrote: >> UPS does not protect against the tech behind the rack unplugging the >> power cable, or an accidental power cycle from exercising the wrong >> switch. :) Both are probably more common causes of failure than a total >> power outage. >> >> Erik Myllymaki wrote: >>> I have been in discussion with 3ware support and after adjusting some >>> settings, the 3ware card in RAID 1 gets better performance than the >>> single drive. I guess this had everything to do with the write (and >>> maybe read?) cache. >>> >>> Of course now i am in a dangerous situation - using volatile write >>> cache without a BBU. >>> >>> If I were to use a UPS to ensure a soft shutdown in the event of power >>> loss, am I somewhat as safe as if I were to purchase a BBU for this >>> RAID card? > > Nor does it prevent an electrician from dropping a tiny piece of wire > into a power conditioner, causing a feedback that blows the other two > power conditioners, all three industrial UPSes, and the switch that > allows the Diesal generator to take over. > > When that happened to me, I had the only database server in the company > to come back up 100% in tact. You can guess by now I also had the only > database server with battery backed cache... > > ---------------------------(end of broadcast)--------------------------- > TIP 9: In versions below 8.0, the planner will ignore your desire to > choose an index scan if your joining column's datatypes do not > match
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